Head-shaking and Vibration-induced Nystagmus During and Between the Attacks of Unilateral Ménière’s Disease

Evolution of Vestibular Findings During and Between the Attacks of Meniere Disease: Update

Purpose of Review

The diagnosis of Meniere disease (MD) has based on characteristics of vertigo and findings of audiologic evaluation. This review focuses on the recent findings of the evolution of vestibular function and their underlying physiology during and between the attacks of MD and thus aims to help identify this common disorder with many faces according to the phase.

Recent Findings

During the attacks, the direction of spontaneous nystagmus changes over time, beating initially toward the affected ear (irritative nystagmus), then toward the healthy ear (paretic nystagmus), and finally back toward the affected ear again (recovery nystagmus). Apart from these direction changes, atypical forms of spontaneous nystagmus, such as downbeat, discordant horizontal-torsional, and aperiodic alternating nystagmus, can be observed. Head impulse tests (HITs) are mostly normal during the irritative/recovery phases, but positive in more than half of patients during the paretic phase. By contrast, caloric tests are usually abnormal irrespective of the phases, although paradoxical caloric hyper-responsiveness can be observed in 18% of patients during the irritative/recovery phases. Thus, dissociation in the findings of caloric tests-HITs can be observed during and between the attacks. Horizontal head shaking tends to augment spontaneous nystagmus during each phase, while skull vibration mostly induces nystagmus beating toward the healthy ear irrespective of the phases. During the attacks, ocular vestibular-evoked myogenic potentials (VEMPs) may be enhanced, whereas cervical VEMPs are usually decreased during stimulation of the involved ear.

Summary

Recognizing these evolutions of vestibular findings during and between the attacks of MD would provide insights into its pathophysiology and aid in treatments and diagnosis.

Neurological update: neuro-otology 2023

Much has changed since our last review of recent advances in neuro-otology 7 years ago. Unfortunately there are still not many practising neuro-otologists, so that most patients with vestibular problems need, in the first instance, to be evaluated and treated by neurologists whose special expertise is not neuro-otology. The areas we consider here are mostly those that almost any neurologist should be able to start managing: acute spontaneous vertigo in the Emergency Room-is it vestibular neuritis or posterior circulation stroke; recurrent spontaneous vertigo in the office-is it vestibular migraine or Meniere's disease and the most common vestibular problem of all-benign positional vertigo. Finally we consider the future: long-term vestibular monitoring and the impact of machine learning on vestibular diagnosis.

Vestibular assessment in sudden sensorineural hearing loss: Role in the prediction of hearing outcome and in the early detection of vascular and hydropic pathomechanisms

Introduction

Predicting hearing outcome in sudden sensorineural hearing loss (SSNHL) is challenging, as well as detecting the underlying pathomechanisms. SSNHL could be associated with vestibular damage since cochleo-vestibular structures share the same vascularization, along with being in close anatomical proximity. Whereas viral inflammations and autoimmune/vascular disorders most likely represent the involved aetiologies, early-stage Menière's disease (MD) can also present with SSNHL. Since an early treatment could beneficially influence hearing outcome, understanding the possible etiology plays a pivotal role in orienting the most appropriate treatment. We aimed to evaluate the extent of vestibular damage in patients presenting with SSNHL with or without vertigo, investigate the prognostic role of vestibular dysfunctions on hearing recovery and detect specific lesion patterns related to the underlying pathomechanisms.

Methods

We prospectively evaluated 86 patients with SSNHL. Audio-vestibular investigation included pure-tone/speech/impedance audiometry, cervical/ocular-VEMPs, vHIT and video-Frenzel examination. White matter lesions (WML) were evaluated on brain-MRI. Patients were followed-up and divided into "SSNHL-no-vertigo," "SSNHL+vertigo" and "MD" subgroups.

Results

Hearing was more impaired in "SSNHL+vertigo" patients who exhibited either down-sloping or flat-type audiograms, and was less impaired in "MD" where low frequencies were mostly impaired (p < 0.001). Otolith receptors were more frequently involved than semicircular canals (SCs). Although the "SSNHL-no-vertigo" subgroup exhibited the lowest vestibular impairment (p < 0.001), 52% of patients developed otolith dysfunctions and 72% developed nystagmus. Only "MD" subjects showed anterior SC impairment and upbeating spontaneous/positional nystagmus. They more frequently exhibited cervical-VEMPs frequency tuning (p = 0.036) and ipsilesional spontaneous nystagmus (p < 0.001). "SSNHL+vertigo" subjects presented with more frequently impaired cervical-VEMPs and posterior SC and with higher number of impaired receptors (p < 0.001). They mainly exhibited contralesional spontaneous and vibration-induced nystagmus (p < 0.05) and only they showed the highest WML score and "vascular" lesion patterns (p < 0.001). Concerning the outcomes, hearing was better in "MD" and worse in "SSNHL+vertigo" (p < 0.001). Hearing recovery was mostly affected by cervical-VEMPs impairment and the number of involved receptors (p < 0.05). Patients with "vascular" lesion patterns presented with the highest HL degree and WML score (p ≤ 0.001), while none of them exhibited a complete hearing recovery (p = 0.026).

Conclusions

Our data suggest that vestibular evaluation in SSNHL can provide useful information on hearing recovery and underlying aetiologies.

Different Types of Mastoid Process Vibrations Affect Dynamic Margin of Stability Differently

The vestibular system is critical for human locomotion. Any deteriorated vestibular system leads to gait instability. In the past decades, these alternations in gait patterns have been majorly measured by the spatial-temporal gait parameters and respective variabilities. However, measuring gait characteristics cannot capture the full aspect of motor controls. Thus, to further understand the effects of deteriorated vestibular system on gait performance, additional measurement needs to be taken into consideration. This study proposed using the margin of stability (MOS) to identify the patterns of dynamic control under different types of mastoid vibrations in walking. This study hypothesized that (1) using the MOS method could facilitate the understanding of another aspect of motor control induced by different types of mastoid vibrations, and (2) applying the mastoid vibrations could induce the asymmetric MOS. Twenty healthy young adults were recruited. Two electromechanical vibrotactile transducers were placed on the bilateral mastoid process to apply different types of vestibular vibrations (bilateral, unilateral, and no vibration). A motion capture system with eight cameras was used to measure the MOSap (margin of stability in the anterior-posterior direction), MOSml (margin of stability in the medial-lateral direction), and respective variabilities. The results were in line with the hypotheses that both bilateral and unilateral mastoid vibrations significantly increased MOSap (p = 0.036, p < 0.001), MOSml (p = 0.012, p < 0.001), and respective variabilities p = 0.001, p < 0.001; p = 0.001, p < 0.01 when compared to the no vibration condition. Also, significantly larger MOSml (p = 0.001), MOSml variability (p < 0.023), MOSap (p < 0.001), and MOSap variability (p = 0.002) were observed under the unilateral vibration condition than that observed under the bilateral vibration condition. The above-mentioned result found that different types of mastoid vibrations affected the MOS differently, suggesting different patterns of control mechanisms under different sensory-conflicted situations. Besides, a significant difference between the dominant and non-dominant legs was observed in MOSml. Moreover, applying the unilateral mastoid vibrations induced a greater symmetric index of MOSml, suggesting that more active control in balance was needed in the medial-lateral than in the anterior-posterior direction.

Discordant horizontal-torsional nystagmus: a sign of posterior semicircular canal dysfunction

In central as well as peripheral vestibular lesions, right-beating horizontal nystagmus is almost always associated with clockwise (top poles of the eyes beating to the right ear) torsional nystagmus when observed and vice versa (concordant nystagmus). This study aimed to determine the etiologies and mechanisms of horizontal and torsional nystagmus beating in the opposite directions (discordant nystagmus). We reviewed the medical records of 16 consecutive patients with discordant horizontal-torsional nystagmus who had been evaluated at the dizziness clinics of Seoul National University Bundang Hospital (n = 11, from March 2003 to March 2021) and Korea University Medical Center (n = 5, from March 2019 to March 2021). The underlying etiologies included inferior vestibular neuritis (n = 7), Meniere's disease (n = 4), internuclear ophthalmoplegia (n = 3), medullary hemorrhage (n = 1), and normal pressure hydrocephalus (n = 1). The torsional nystagmus decreased during the gaze in the same direction (for instance, during rightward gaze in clockwise nystagmus) and increased during the gaze in the opposite direction. Head-impulse tests (HITs) were positive for the ipsilesional posterior canal (PC) in all 11 patients with unilateral peripheral vestibulopathy and two of the three patients with unilateral central vestibulopathy. Discordant horizontal-torsional nystagmus may be observed in peripheral as well as central lesions. Given the findings of HITs and modulation of spontaneous nystagmus during lateral gazes, discordant horizontal-torsional nystagmus may be ascribed to selective damage of the excitatory or inhibitory pathway from the PC that innervates the ipsilateral superior oblique and contralateral inferior rectus muscles.

Post headshake nystagmus: further correlation with other vestibular test results

BACKGROUND

It is generally accepted that headshake nystagmus (HSN) is generated from an asymmetrical peripheral vestibular input and a correlation exists between HSN and canal paresis. There have been limited reports, however, how HSN correlates with the more recently introduced tests of vestibular function.

AIMS/OBJECTIVES

To evaluate the correlation between HSN and unilateral weakness on caloric testing, high-frequency vestibulo-ocular reflex (VOR) function on video head impulse testing (VHIT) and otolith function determined by vestibular evoked myogenic potentials (VEMPs).

METHODS

A retrospective study of all patients who underwent complete vestibular function testing at our tertiary referral center from 2016 to 2019 was performed. Demographic data, clinical diagnosis (where available), the results of video-nystagmography, vHIT, and VEMPs were evaluated.

RESULTS

Of the 1499 patients in the study period, 101 (6.7%) had HSN. Vestibular test abnormalities were more common in patients with HSN. The sensitivity of HSN for underlying pathology was low in comparison with vestibular testing. However, HSN demonstrated a high specificity.

CONCLUSIONS AND SIGNIFICANCE

HSN generation is likely more complex than caloric-induced nystagmus, probably due to additional variables within the vestibular system. HSN may provide clinicians with additional information concerning high-frequency VOR function involving lateral semicircular and otolith dysfunction.

Clinical, oculographic and vestibular test characteristics of Ménière's disease

Seventy Ménière's disease (MD) patients with spontaneous vertigo (100%), unilateral aural fullness (57.1%), tinnitus (78.6%), and subjective hearing loss (75.7%) self-recorded nystagmus during their episodes of vertigo using portable video oculography goggles. All demonstrated ictal spontaneous nystagmus, horizontal in 94.3% (n = 66) and vertical in 5.7% (n = 4), with a mean slow-phase velocity (SPV) of 42.8 ± 31.1°/s (range 5.3-160.1). Direction reversal of spontaneous horizontal nystagmus was captured in 58.6%, within the same episode in 34.3%, and over different days in 24.3%. In 18.6%, we observed ipsiversive then contraversive nystagmus, and in 12.9% contraversive to ipsiversive direction reversal. Ictal nystagmus SPV (42.8 ± 31.1°/s) was significantly faster than interictal (1.4 ± 3.1°/s, p < 0.001, CI 34.277-48.776). Compared to age-matched healthy controls, interictal video head impulse test gains in MD ears were significantly lower, cumulative and first saccade (S1) amplitudes were significantly larger, and S1 peak velocities were significantly faster (p = 0.038/0.019/0.008/ < 0.001, CI 0.002-0.071/0.130-1.444/0.138-0.909/14.614-41.506). Audiometry showed asymmetrically increased thresholds in 100% of MD ears (n = 70). Significant caloric, air-conducted (AC) cervical vestibular-evoked myogenic potential (VEMP), and AC ocular VEMP asymmetries were found in 61.4, 37.9, and 44.4% of patients (MD ear reduced). Transtympanic electrocochleography tested in 36 ears (23 patients) showed 81.8% of MD ears had a positive result for hydrops (either a summating potential at 1/2 kHz < - 6 µV, or an SP/AP ratio > 40%). Using ictal nystagmus findings of SPV > 12°/s, and a caloric canal paresis > 25%, we correctly separated a diagnosis MD from Vestibular Migraine with a sensitivity and specificity of 95.7% and 85.1% (CI 0.89-0.97).

Skull Vibration-Induced Nystagmus Test in a Human Model of Horizontal Canal Plugging

Background/Aim: the aim of this study was to assess the skull vibration-induced nystagmus test (SVINT) results and vestibular residual function after horizontal semicircular canal (HSCC) plugging. Methods: In this retrospective chart review performed in a tertiary referral center, 11 patients who underwent unilateral horizontal semicircular canal plugging (uHSCCP) for disabling Menière’s disease (MD) were included. The skull vibration-induced nystagmus (SVIN) slow-phase velocity (SPV) was compared with the results of the caloric test (CaT), video head impulse test (VHIT), and cervical vestibular-evoked myogenic potentials (cVEMP) performed on the same day. Results: Overall, 10 patients had a strong SVIN beating toward the intact side (Horizontal SVIN-SPV: 8.8°/s ± 5.6°/s), 10 had a significant or severe ipsilateral CaT hypofunction, 10 had an ipsilateral horizontal VHIT gain impairment, and 3 had altered cVEMP on the operated side. Five had sensorineural hearing worsening. SVIN-positive results were correlated with CaT and horizontal VHIT (HVHIT) results (p < 0.05) but not with cVEMP. SVIN-SPV was correlated with CaT hypofunction in % (p < 0.05). Comparison of pre- and postoperative CaT % hypofunction showed a significant worsening (p = 0.028). Conclusion: SVINT results in a human model of horizontal canal plugging are well correlated with vestibular tests exploring horizontal canal function, but not with cVEMP. SVINT always showed a strong lesional nystagmus beating away from the lesion side. SVIN acts as a good marker of HSCC function. This surgical technique showed invasiveness regarding horizontal canal vestibular function.

Agreement between the Skull Vibration-Induced Nystagmus Test and Semicircular Canal and Otolith Asymmetry

BACKGROUND

 How significant asymmetries in otolith organ function in the presence of symmetrical and asymmetrical semicircular canal function influence skull vibration-induced nystagmus testing (SVINT) has not been well described.

PURPOSE

 The aim of the study is to examine the agreement between SVINT and caloric testing, ocular vestibular-evoked myogenic potentials (oVEMP), and cervical vestibular-evoked myogenic potentials (cVEMP) for detecting asymmetric vestibular function.

RESEARCH DESIGN

 This is a retrospective study of patients presenting with the chief complaint of vertigo, dizziness, or imbalance.

STUDY SAMPLE

 A total of 812 patients were studied with a median age at testing of 59 years (interquartile range 46-70; range 18-93) and included 475 (59%) women.

INTERVENTION

 Either the monothermal warm caloric test or alternate binaural bithermal caloric test, oVEMP, and cVEMP tests were administered to all patients. All patients underwent the SVINT prior to vestibular laboratory testing.

DATA COLLECTION AND ANALYSIS

 Agreement between tests categorized as normal versus abnormal was summarized using percent concordance (PC). Sensitivity and specificity values were calculated for SVINT compared with other tests of vestibular function.

RESULTS

 There was higher agreement between ipsilateral and contralateral SVINT with the caloric test (PC = 80% and 81%, respectively) compared with oVEMP (PC = 63% and 64%, respectively) and cVEMP (PC = 76% and 78%, respectively). Ipsilateral and contralateral SVINT showed higher sensitivity for the caloric test (sensitivity = 47% and 36%, respectively) compared with oVEMP (sensitivity = 26% and 21%, respectively), or cVEMP (sensitivity = 33% vs. 27%, respectively). Specificity of SVINT was high (>80%) for all assessments of vestibular function.

CONCLUSION

 The presence of SVIN is a useful indicator of the asymmetry of vestibular function between the two ears when making judgments about semicircular canal asymmetry but is less sensitive to asymmetries in otolith organ function.

Evolution in the Findings of Head-Impulse Tests During the Attacks of Menière's Disease

OBJECTIVE

To determine the vestibulo-ocular reflex (VOR) performance during the attacks of Menière's disease (MD) using video head-impulse tests (video-HITs) according to each ictal phase.

STUDY DESIGN

Retrospective case series review.

METHODS

We analyzed the results of video-HITs in 24 patients with unilateral definite MD during and between the attacks.

RESULTS

The head impulse gain of the VOR was usually normal (81%, 39 of the 48 semicircular canals [SCCs] in 16 patients) in the affected ear during the irritative or recovery phase, and did not differ from that for each SCC between the attacks (horizontal [HCs], p = 0.412; anterior [ACs], p = 0.920; posterior canals [PCs], p = 0.477). During the paretic phase, however, the head impulse gains of the VOR were equally normal (22/42, 52%) or decreased (20/42, 48%) for the affected ear (42 SCCs in 14 patients). The gains for the HCs were lower during the paretic phase than those between the attacks in the affected ear, while those for the ACs and PCs did not differ (HCs, p = 0.001; ACs, p = 0.158, PCs, p = 0.401). Covert saccades were more frequently observed even in the presence of normal VOR gains during the paretic phase as well.

CONCLUSION

During the attacks of MD, HITs are usually normal during the irritative/recovery phases, but become positive in more than a half of the patients during the paretic phase. This evolution in the ictal findings of HITs may reflect characteristic ictal vestibular discharges in MD and should be considered in evaluating patients with MD according to each ictal phase during the attacks.

Evolution of caloric responses during and between the attacks of Meniere's disease

Caloric tests are useful for disease surveillance of Meniere's disease (MD), although the interpretation of caloric tests remains controversial during the attacks of MD. Therefore, we aimed to characterize the findings of caloric tests during the attacks of MD. We analyzed the results of bithermal caloric tests during and between the attacks in 43 patients with unilateral definite MD. Evaluation was performed during the irritative/recovery phase in 22 and during the paretic phase in 26 patients. During the irritative/recovery phase, less than half of patients (10/22, 45%) showed a caloric asymmetry of more than 25%, lesser responses in the affected ear in six and in the healthy ear in the other four. In contrast, patients usually showed a caloric asymmetry of more than 25% during the paretic phase (19/26, 73%) with a decreased response almost always in the affected ear (18/19, 95%). Between the attacks, caloric asymmetry was found in less than half of the patients (20/43, 47%) with a decreased response almost always in the affected ear (19/20, 95%) when observed. The caloric asymmetry was less during the irritative/recovery phases than between the attacks (p = 0.007). In contrast, the caloric asymmetry was larger during the paretic phase than between the attacks (p = 0.041). The caloric asymmetry decreased during the irritative/recovery phases with an estimated mean difference of 34% (adjusted 95% CI 16-53%, p < 0.001) and 23% (adjusted 95% CI 8-38%, p = 0.002) compared to the paretic and interictal phases. Caloric responses fluctuate during and between the attacks of MD depending on the electrophysiologic status of the vestibular afferents. The results of caloric tests in MD, thus should be interpreted with consideration of each phase when the evaluation was done.

[Effective diagnostics for vertigo, dizziness and equilibrium disorders]

Vertigo, dizziness and equilibrium disorders are symptoms with a variety of causes. First, four cardinal questions (type and duration of the vertigo, triggering factors, accompanying symptoms) must be answered. After that, the search for a spontaneous nystagmus (differentiation of peripheral and central disorder using the HINTS[head impulse, nystagmus, test of skew]-test ) and, as part of a positioning examination, the search for a benign paroxysmal positional vertigo (BPPV) are necessary. If the result is negative an instrument-based receptor-specific examination is carried out. The caloric examination (low-frequency stimulus) tests the horizontal semicircular canal and the superior vestibular nerve, whereas the 3‑D video head impulse test (vHIT, high-frequency stimulus) is used to analyze all three semicircular canals as well as the superior and inferior vestibular nerves. Analysis of the cervical vestibular evoked myogenic potential (cVEMP) checks the function of the sacculus and that of the ocular VEMP (oVEMP) checks the function of the utriculus. The final overall analysis usually gives a definitive diagnosis or at least provides a suspected diagnosis, which then determines the further diagnostic procedure (e.g. targeted radiological diagnostics if vestibular paroxysmia, superior canal dehiscence or a vestibular schwannoma are suspected).

Ictal downbeat nystagmus in Ménière disease: A cross-sectional study

OBJECTIVE

To determine the mechanism of ictal downbeat nystagmus in Ménière disease (MD), we compared the head impulse gain of the vestibulo-ocular reflex (VOR) for each semicircular canal between patients with (n = 7) and without (n = 70) downbeat nystagmus during attacks of MD.

METHODS

We retrospectively analyzed the results of video-oculography, video head-impulse tests, and cervical vestibular-evoked myogenic potentials (VEMPs) in 77 patients with definite MD who were evaluated during an attack.

RESULTS

Pure or predominant downbeat nystagmus was observed in 7 patients (9%) with unilateral MD during the attacks. All 7 patients showed spontaneous downbeat nystagmus without visual fixation with a slow phase velocity ranging from 1.5 to 11.2°/s (median 5.4, interquartile range 3.7-8.5). All showed a transient decrease of the head impulse VOR gains for the posterior canals (PCs) in both ears (n = 4) or in the affected ear (n = 3). Cervical VEMPs were decreased in the affected (n = 2) or both ears (n = 2) when evaluated during the attacks. Downbeat nystagmus disappeared along with normalization of the VOR gains for PCs after the attacks in all patients. During the attacks, the head impulse VOR gains for the PC on the affected side were lower in the patients with ictal downbeat nystagmus than in those without (Mann-Whitney U test, p < 0.001), while the gains for other semicircular canals did not differ between the groups.

CONCLUSION

Downbeat nystagmus may be observed during attacks of MD due to an asymmetry in the vertical VOR or saccular dysfunction. MD should be considered in recurrent audiovestibulopathy and ictal downbeat nystagmus.

Head-Shaking Nystagmus in the Early Stage of Unilateral Meniere's Disease

OBJECTIVES

The aim of the present study was to evaluate the ability of head-shaking nystagmus (HSNy), evoked after the resolution of a vertigo spell, to predict an imminent crisis in the early stage of Meniere's disease (MD).

MATERIALS AND METHODS

A total of 20 patients in the early stage of MD were included in the study. The head-shaking test (HST) was performed twice, during the first visit within 24 h of vertigo spell (T0) and 48 h later (T1). The onset of a new vertigo episode during the 2 weeks following the first visit was recorded in each patient's medical record. The sensitivity and specificity of HSNy toward predicting a new vertigo episode were calculated.

RESULTS

At T0, an evoked ipsilesional HSNy in 15 (75%) patients was observed; in four of them, the HSNy had a biphasic component. The HSNy was present and persistent at T1 in 8 (42.1%) patients; among these cases, 6 patients had ipsilesional HSNy, and 2 patients a contralesional HSNy. None of the patients presented with a biphasic HSNy at T1. Seven (36.8%) patients experienced the recurrence of a vertigo crisis. Among these, 6 patients had ipsilesional HSNy at T1. Only 8 patients with ipsilesional HSNy at T0 did not have recurrence. The sensitivity of the ipsilesional HSNy in predicting the recurrence of vertigo in patients with MD was 100% at T0 and 85.7% at T1. The specificity was 46.6% and 100% at T0 and T1, respectively.

CONCLUSION

The HST can be a useful test in the early stages of MD to predict a new vertigo attack.

Intralabyrinthine Schwannoma: Distinct Features for Differential Diagnosis

Objectives: The aim of this study was to delineate the clinical and laboratory features suggestive of intralabyrinthine schwannoma (ILS). Methods: We compared the clinical features of 16 patients with ILS, who had been diagnosed at the Seoul National University Bundang Hospital from 2003 to 2018, with those of 18 patients with symptomatic unilateral intracanalicular schwannoma and randomly selected 20 patients with definite or probable unilateral Meniere's disease (MD). Results: Patients with ILS presented with either recurrent spontaneous dizziness/vertigo combined with auditory symptoms (n = 8), isolated auditory symptoms without dizziness/vertigo (n = 7), or recurrent spontaneous dizziness/vertigo without auditory symptoms (n = 1). Most patients reported no improvement (n = 11) or worsening (n = 1) of the symptoms despite medical treatments including intratympanic (n = 5) or intravenous steroids (n = 2). Conventional brain MRIs failed to detect ILS in about a half of the patients (7/16, 44%). However, ILS showed a filling defect on 3-dimensional (3D) heavily T2-weighted MRIs (n = 12), and nodular enhancement on 3D contrast-enhanced T1 (n = 15) or FLAIR MRIs (n = 13) targeted for the inner ear. Compared to MD or intracanalicular schwannoma, ILS showed mostly abnormal head-impulse tests (HITs, p = 0.001). In contrast, the incidence of canal paresis did not differ among the groups (p = 0.513). Conclusion: ILS may mimic MD by presenting recurrent dizziness/vertigo and auditory symptoms. ILS should be suspected in patients with recurrent audiovestibulopathy especially when (1) the duration of the dizziness is not typical for MD, (2) the patients do not respond to medical treatments, or (3) HITs are abnormal.

Capturing acute vertigo

Objective

To facilitate the diagnosis of vestibular disorders by patient-initiated capture of ictal nystagmus.

Methods

Adults from an Australian neurology outpatient clinic reporting recurrent vertigo were recruited prospectively and taught to self-record spontaneous and positional nystagmus at home while symptomatic, using miniature video-oculography goggles. Consenting patients with ictal videorecordings and a final unblinded clinical diagnosis of Ménière disease (MD), vestibular migraine (VM), or benign paroxysmal positional vertigo (BPPV) were included.

Results

Ictal eye videos of 117 patients were analyzed. Of 43 patients with MD, 40 showed high-velocity spontaneous horizontal nystagmus (median slow-phase velocity [SPV] 39.7°/s; 21 showed horizontal nystagmus reversing direction within 12 hours [24 on separate days]). In 44 of 67 patients with VM, spontaneous horizontal (n = 28, 4.9°/s), upbeating (n = 6, 15.5°/s), or downbeating nystagmus (n = 10, 5.1°/s) was observed; 16 showed positional nystagmus only, and 7 had no nystagmus. Spontaneous horizontal nystagmus with SPV >12.05°/s had a sensitivity and specificity of 95.3% and 82.1% for MD (95% confidence interval [CI] 0.84–0.99, 0.71–0.90). Nystagmus direction change within 12 hours was highly specific (95.7%) for MD (95% CI 0.85–0.99). Spontaneous vertical nystagmus was highly specific (93.0%) for VM (95% CI 0.81–0.99). In the 7 patients with BPPV, spontaneous nystagmus was absent or <3°/s. Lying affected-ear down, patients with BPPV demonstrated paroxysmal positional nystagmus. Median time for peak SPV to halve (T50) was 19.0 seconds. Patients with VM and patients with MD demonstrated persistent positional nystagmus (median T50; 93.1 seconds, 213.2 seconds). T50s <47.3 seconds had a sensitivity and specificity of 100% and 77.8% for BPPV (95% CI 0.54–1.00, 0.64–0.88).

Conclusion

Patient-initiated vestibular event monitoring is feasible and could facilitate rapid and accurate diagnosis of episodic vestibular disorders.

Vertigo Induced During Coitus

Objectives: The aim of this study was to describe the clinical features of vertigo developed during sexual intercourse. Methods: We retrospectively reviewed the clinical and laboratory findings of seven patients who reported recurrent vertigo during sexual intercourse. Results: All the patients reported spinning sensation for a few minutes to 1 h, which developed during the coitus. Most patients (6/7, 86%) reported associated auditory symptoms including tinnitus (n = 4), ear fullness (n = 2), autophony (n = 1), hearing impairment (n = 1), or hyperacusis (n = 1). Four patients reported the vertigo to occur exclusively during sexual intercourse or masturbation while the other three patients also experienced vertigo during other physical activities. Underlying disorders included Meniere's disease (n = 3), superior canal dehiscence (n = 1), and high jugular bulb anomaly (n = 1) while the remaining two patients had no identifiable causes. Conclusions: Various disorders may cause coital vertigo probably due to disruption of the mechanism that normally refrains the increased intracranial pressure from being directly transferred to the peripheral vestibular organs.

Recurrent spontaneous vertigo with interictal headshaking nystagmus

Objective

To define a disorder characterized by recurrent spontaneous vertigo (RSV) of unknown etiology and interictal headshaking nystagmus (HSN).

Methods

We characterized HSN in 35 patients with RSV-HSN compared to that recorded in randomly selected patients with compensated vestibular neuritis (VN), vestibular migraine (VM), and Ménière disease (MD).

Results

The estimated time constant (TC) of the primary phase of HSN was 12 seconds (95% confidence interval [CI] 12–13) in patients with RSV-HSN, which was larger than those in patients with VN (5 seconds, 95% CI 4–5), VM (5 seconds, 95% CI 5–6), or MD (6 seconds, 95% CI 5–6). TCs of the horizontal vestibulo-ocular reflex were also larger during the rotatory chair test in patients with RSV-HSN. Among the 35 patients with RSV-HSN, 7 showed vigorous long-lasting HSN with a peak slow-phase velocity >50.0°/s. In 5 patients (5 of 7, 71%) with vigorous HSN, HSN could have been induced even with headshaking for only 2 to 5 seconds. Long-term prognosis was favorable, with a resolution or improvement of the symptoms in more than half of the patients during the median follow-up of 12 (range 2–58) years from symptom onset. None developed VM, MD, or cerebellar dysfunction during the follow-up.

Conclusion

The clinical features and characteristics of HSN in our patients indicate a hyperactive and asymmetric velocity-storage mechanism that gives rise to intermittent attacks of spontaneous vertigo probably when marginal compensation of underlying pathology is disrupted by endogenous or exogenous factors.

Treatment of vestibular disorders with weak asymmetric base-in prisms: An hypothesis with a focus on Ménière's disease

BACKGROUND:

Regular treatments of Ménière’s disease (MD) vary largely, and no single satisfactory treatment exists. A complementary treatment popular among Dutch and Belgian patients involves eyeglasses with weak asymmetric base-in prisms, with a perceived high success rate. An explanatory mechanism is, however, lacking.

OBJECTIVE:

To speculate on a working mechanism explaining an effectiveness of weak asymmetric base-in prims in MD, based on available knowledge.

METHODS:

After describing the way these prisms are prescribed using a walking test and its effect reported on, we give an explanation of its underlying mechanism, based on the literature.

RESULTS:

The presumed effect can be explained by considering the typical star-like walking pattern in MD, induced by a drifting after-image comparable to the oculogyral illusion. Weak asymmetric base-in prisms can furthermore eliminate the conflict between a net vestibular angular velocity bias in the efferent signal controlling the VOR, and a net re-afferent ocular signal.

CONCLUSIONS:

The positive findings with these glasses reported on, the fact that the treatment itself is simple, low-cost, and socially acceptable, and the fact that an explanation is at hand, speak in favour of elaborating further on this treatment.

The Skull Vibration-Induced Nystagmus Test of Vestibular Function-A Review

A 100-Hz bone-conducted vibration applied to either mastoid induces instantaneously a predominantly horizontal nystagmus, with quick phases beating away from the affected side in patients with a unilateral vestibular loss (UVL). The same stimulus in healthy asymptomatic subjects has little or no effect. This is skull vibration-induced nystagmus (SVIN), and it is a useful, simple, non-invasive, robust indicator of asymmetry of vestibular function and the side of the vestibular loss. The nystagmus is precisely stimulus-locked: it starts with stimulation onset and stops at stimulation offset, with no post-stimulation reversal. It is sustained during long stimulus durations; it is reproducible; it beats in the same direction irrespective of which mastoid is stimulated; it shows little or no habituation; and it is permanent—even well-compensated UVL patients show SVIN. A SVIN is observed under Frenzel goggles or videonystagmoscopy and recorded under videonystagmography in absence of visual-fixation and strong sedative drugs. Stimulus frequency, location, and intensity modify the results, and a large variability in skull morphology between people can modify the stimulus. SVIN to 100 Hz mastoid stimulation is a robust response. We describe the optimum method of stimulation on the basis of the literature data and testing more than 18,500 patients. Recent neural evidence clarifies which vestibular receptors are stimulated, how they cause the nystagmus, and why the same vibration in patients with semicircular canal dehiscence (SCD) causes a nystagmus beating toward the affected ear. This review focuses not only on the optimal parameters of the stimulus and response of UVL and SCD patients but also shows how other vestibular dysfunctions affect SVIN. We conclude that the presence of SVIN is a useful indicator of the asymmetry of vestibular function between the two ears, but in order to identify which is the affected ear, other information and careful clinical judgment are needed.

Neuro-otology- some recent clinical advances

Vestibular disorders manifesting as vertigo, chronic dizziness and imbalance are common problems in neurological practice. Here, we review some recent interesting and important advances in diagnosis of vestibular disorders using the video head impulse test and in the management of benign positional vertigo and migrainous vertigo.

Comparison of caloric and head-impulse tests during the attacks of Meniere's disease

OBJECTIVES/HYPOTHESIS

To aid in diagnosis of Meniere's disease (MD) during the attacks using caloric and head-impulse tests (HITs).

STUDY DESIGN

Retrospective case series review.

METHODS

We analyzed the results of bithermal caloric and HITs during the attacks in 16 patients with MD. Quantitative analyses of HITs were conducted using a magnetic search coil technique.

RESULTS

In unilateral MD (14 patients, 42 semicircular canals), the head impulse gain of the vestibulo-ocular reflex (VOR) was either normal (28 of 42, 67%), decreased (8 of 42, 19%), or increased (6 of 42, 14%) for each semicircular canal in the affected ear. Likewise, the head impulse VOR gain was either normal (29 of 42, 69%), increased (11 of 42, 26%), or decreased (2 of 42, 5%) in the intact ear. The VOR gain for the horizontal canal was significantly lower on the affected side (P = 0.013). However, the VOR gains for the anterior and posterior canals did not differ between the sides (P = 0.270, P = 0.282). In bilateral MD (two patients, 12 semicircular canals), the VOR gain was either decreased (6 of 12, 50%) or normal (6 of 12, 50%) in either ear. In contrast, the caloric responses were usually decreased in the affected ear (7 of 11, 64%, including one with bilateral MD).

CONCLUSION

During the attacks of MD, HITs showed varied results between the ears and among the canals, although the caloric responses were usually decreased in the involved ear. These dissociations suggest a frequency-dependent impairment of canal function or mechanical property of the endolymphatic hydrops during the attacks of MD.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:702-708, 2017.